Cranes of this type generally are configured as crawler cranes and known per se. The ballast carriage here is used to be able to also move the crane with the derrick ballast while the crane is unloaded, or to rotate the crane under partial load. The derrick ballast each is suspended at the head piece of the derrick boom.
The ballast carriages of the so-called crawler cranes previously have been configured as a special component of the entire crane with few large wheels. However, these ballast carriages involve the disadvantage that they are only suitable for use on the crane and thereby substantially increase the investment sum for the entire crane.
Simply omitting the ballast carriage in particular in constructions of large cranes, as they are increasingly required for example for building nuclear power plants, is not possible.
Therefore, it is the object of the present disclosure to develop a generic crane such that even when constructed as large crane it can do without an additional individually constructed ballast carriage adapted to the respective large crane.
In accordance with the present disclosure, this object is solved by a crane with a travelling undercarriage, an uppercarriage rotatably mounted on the same with a luffing boom and derrick boom arranged on the same, and a ballast carriage connectable with the uppercarriage via a coupling element, in which the ballast carriage is a heavy-duty transport device with separate drive and separate drive controller, wherein this drive controller can be influenced as a result of the movement of the crane. The heavy-duty transport device may be of a standard variety, including having standardized sizes, weights, and/or other such features.
In accordance with the present disclosure, a standard heavy-duty transport vehicle therefore is used, as it is employed already in a large number by the users of cranes for moving heavy loads, such as bridge elements or parts of oil rigs. Such heavy-duty transport vehicles have a separate drive and a separate drive controller. Since the driving forces of a heavy-duty transport device or a heavy-duty transport vehicle are relatively high, a high lateral force can be introduced to the crane when rotating the crane. This high lateral force is transmitted to the derrick boom, at whose head piece the derrick ballast is suspended. However, since a derrick boom basically represents a pressure rod, it is extremely sensitive to lateral forces. In accordance with the present disclosure, the drive controller of the heavy-duty transport device therefore is formed such that it can be influenced as a result of the movement of the crane.
Due to this influence, the drive controller of the heavy-duty transport device in accordance with one embodiment can be configured such that when rotating the crane it automatically determines the corresponding steering center and in towing operation behind the crane steers, accelerates or decelerates automatically. As another example, the drive controller of the heavy-duty transport device may adjust operation of the heavy-duty transport drive in response to movement of the crane, such as in response to a length of the variable length coupling element.
Even if in another variant the drive controller of the ballast carriage has not been upgraded such that it can automatically perform the aforementioned controls, the fact that the drive controller can be influenced by the crane movement in accordance with the present teaching ensures that for the case that a steering error of the heavy-duty transport device leads to an undesired introduction of force into the coupling element between the uppercarriage and the ballast carriage the separate drive of the heavy-duty transport device stops the entire system, i.e. both the crane and the heavy-duty transport device, so that for example by manual control the ballast carriage can again by moved into the desired position by means of its own drive. Subsequently, operation of the crane can again be continued.
Further preferred aspects of the present disclosure can be taken from the sub-claims following the main claim.
The coupling element between the uppercarriage and the ballast carriage can be designed to be variable in its length and can include a length sensor. The coupling element advantageously can consist of two articulated rods which are coupled via a hydraulic cylinder acting as length sensor. The length of the hydraulic cylinder now is monitored via a corresponding sensor communicating with one or more of the drive controllers. Each change in stroke of the hydraulic cylinder is detected and converted into an actuation signal, which can be used for correction of the steering error or for switching off. In towing operation behind the crane, the ballast carriage can be accelerated, decelerated or also stopped, depending on the deflection of the piston in the hydraulic cylinder.
In accordance with another preferred aspect of the present disclosure, the ballast is placed on a pallet which can be mounted on the heavy-duty transport device and be connected with the same. In this way, a heavy-duty transport device already present with the user can be employed as ballast carriage in a particularly easy way. It must only be ensured that the corresponding pallet is connected with the heavy-duty transport vehicle after being mounted correspondingly.
In accordance with a further preferred embodiment, a rigid guide frame is created as coupling element between the uppercarriage and an articulation point on the pallet picking up the ballast and putting the same down on the ballast carriage, wherein the guide frame is movably mounted with respect to the articulation point in the articulation region such that a relative longitudinal movement with a deviation from a neutral position can be detected and can be converted into an actuation signal for the drive controller of the heavy-duty transport device.
This guide frame provided as coupling element has such a great stability that it introduces all the lateral forces, which as a result of travelling and rotating the entire system of crane and heavy-duty transport device act on the same, into the uppercarriage and here in particular into the turntable frame.
Advantageously, the slewing gear transmission of the crane is switched for concentricity when travelling or rotating, in order to prevent an overload of the guide frame. However, the guide frame can also be dimensioned such that when the brake used for braking the rotary movement of the uppercarriage around the undercarriage is engaged, the brakes will slip through before the guide frame as a whole is overloaded.
In accordance with an advantageous development of the above-described preferred variant, the relative longitudinal movement is realized by a longitudinal guide with a pivot pin such that both a longitudinal movement and a rotary movement is permitted, whereas no movement is permitted in transverse direction. By restricting the movement in transverse direction it is prevented that undesired lateral forces are transmitted to the derrick boom.
In accordance with a further development of this variant, it should be noted that the pallet hangs on pendulums consisting of rods, which at their upper end are articulated to the rigid guide frame and at their lower end to the pallet directly or indirectly via spherical plain bearings. To avoid a too much inclined position of the heavy-duty transport device and in particular of the ballast piled up on the same during a possible relative movement between crane and heavy-duty transport device, the pendular movement can be limited by emergency stops to be provided correspondingly.
Quite particularly advantageously, the pendular movement can be detectable via measuring means, preferably angle sensors, such that due to the measured variables detected actuation signals can be generated for the drive controller.
For the case that the crane must be moved without load over a greater distance, the coupling element can be separable from the uppercarriage and/or ballast carriage, so as to move crane and heavy-duty transport device independent of each other.
Further features, details and advantages of the present disclosure will be explained in detail below with reference to embodiments illustrated in the drawing, in which: